The purpose of this proposal is to request a Blastocyst Injection Station (BIS) to facilitate the generation of chimeric embryos and mice from donor embryos and gene-targeted embryonic stem (ES) cells at the Medical University of South Carolina (MUSC). Chimeric embryos are used for the generation of gene-targeted mutant and knockout transgenic mice and for the study of gene function in the context of the whole individual. The components of this station are a high-powered inverted microscope with optical capabilities for viewing ES cells and blastocyst-stage embryos simultaneously, micromanipulator equipment, a vibration-free support table, and monitoring and recording equipment. This equipment is being requested by a group of 29 users from 6 departments within the MUSC College of Medicine. Specific aims are to: 1. Obtain a blastocyst injection system capable of simultaneously visualizing blastocyst-stage embryos and ES cells and manipulating the blastocysts and ES cells such that ES cells are injected into the blastocoel cavity of the blastocysts. 2. Use this equipment to enhance the research productivity of NIH-funded investigators at MUSC and to improve the research efficiency and competitiveness of research faculty and trainees. 3. Use this equipment to foster independent research by junior investigators in the upcoming user group and enhance their ability to compete successfully for NIH grant funds. 4. Use this equipment to stimulate interdisciplinary research among the user group.